The use of the optical fibers for transmission of signals is of ever increasing importance and offers distinct advantages in many circumstances over conventional electrical and electronic techniques. In addition to transmitting light signals along optical fiber waveguides, from one location to another, it is frequently necessary or desirable to be able to split the beam into parts having predetermined proportions of the original signal intensity and a device having that capability will be referred to herein as a beam splitter. In the past this has only been accomplished by passing the light signal through a filter with the interrelation of optical fiber waveguides to the filter being via complicated apparatus.